You make several excellent points, Steve. I appreciate the feedback. If none of these work out, I'll fall back on a 10'X12' Cedar-Built, which would probably be better functionally than all of these, but I just love the look of an octagon. I have a border with giant curves and a circular vegie garden in the center, so an octagon would fit in visually so well. One thing I'm trying to do is prove that a garden designed for birds, insects, and native plants can be beautiful as well. It would give me so much pleasure just to look at a beautiful gazebo among the lupines. I remember reading that one gazebo somewhere had a skylight option, and at least one vents at the roof, but I can't seem to find those in all my bookmarked pages. I've e-mailed all the sellers a list of questions, and I'm putting all the info into a comparison chart. Some give a wind rating, so I'll add that to my list to ask about. "Fortunately," I can't afford it for a year, so there's plenty of time to research it all. I'd like to use the GH as much as possible, almost year-round. I envision attempting the system Eliot Coleman writes about. I'd like to start seeds to plant out later, perhaps leave tomatoes inside all summer to protect them from the deer, add some long-season plants like peppers and melons, and start a second cool-season crop (maybe start them outdoors) to overwinter in the GH. It doesn't need to be fancy or pretty or roomy or comfortable inside for people, though. I'm wondering if an unglazed roof could be a net benefit, catching the winter sun but avoiding the hottest, most direct rays of summer. If insulated and vented, it could also help moderate temperatures in winter or summer. I'm interested in some solar panels to mount on the roof, like the 45-watt 12"X36" panel kits from Harbor Freight, to power a fan and lights. I have heavy-duty extension cords and an outside receptacle if necessary. I don't want to heat the GH, except maybe with an electric heater in a rare cold spell. (Since I moved back to Montana in 2009, winters here have been incredibly mild compared to 30 years ago. One year an early freeze made the brown leaves stay on the trees all winter. It was in the 40s most days, with hardly any snow; like a very long November. We went two years without getting below zero. It's been in the 40s lately and a some hardy souls have been paddle-boarding on the river.) Forever Redwood, with the #5 gazebo, replied right away, and they'd help me customize it. They mentioned making sure a skylight doesn't leak. Their cupola isn't normally vented, but they could make it vent, and there are three small windows near the top of the walls that open. Their glazing is bronzed Lexan acrylic. They also offer a 10% annual mid-winter online purchase discount, and a 10% discount for waiting 12 weeks for delivery. And you can choose from 3 different heights of base wall (24", 30", 36"). They're looking like the favorite at the moment. The one in the #3 photo is a strong contender, because it's delivered fully assembled. Their site used the word "insulated," so I'm trying to find out what they meant. And, as you mention, they have the most glazing (on 5 of the walls). The one in the #1 photo allows you to pay extra to insulate roof, walls, or floor. And you can get a cedar interior finish. Thanks again for your suggestions.

Ok, I'll look for a more powerful and brighter light bulb. I'm going to be moving most of my seedlings outdoors as soon as they start growing their true leaves, but I guess I could start doing that now. Sorry, I'm new at this. I watched an episode of Good Eats about melons which lead to me hearing about Charentais and how good they are. I researched, to find out, to enjoy them, my best bet would be to grow them. So, I've been scouring the internet for hours the past 3 weeks looking up how to grow these melons the right way, and seeing if I can get them to grow indoors. See, I'm a college student, and currently, I'm staying at my father's house, which I can go outside and plant them. But, when I go back to college, I'm in a 250sqft studio to myself with no garden or anything. So, I want to be able to enjoy this fruit while I'm at school. That's why I made the greenhouse. I probably should have explained this in my first post, but I want to be able to grow these indoor while I'm at school during its off season.

Thanks for the feedback! As to the 'why' of it, well, bc I am an optimist (hence the gardening) and maybe the greenhouse will look a little more dreamy and less like a 209$ greenhouse that it is....if it isn't metal-looking. And painting cedar IS against God, nature and all the design magazines, but I am trying for a silk purse here! Again, the trouble started when I discovered how close I was to the nice greenhouse place up the road. Seeing bespoke, charming greenhouses was great, but a little heartbreaking, knowing DH doesn't care about gardening and would in no way be behind spending the $ for those. Heck, he glowered all night about the scary HF one! I will let you know if reason or art wins out!

On a south facing wall I don't think the top color will have much effect. I would just use 4yr IR greenhouse poly for the entire covering. The IR poly gives a diffused light that is less harsh on the plants and gives more uniform light. I'd make the frame out of white Schedule 40 3/4 or 1 inch plastic water pipe with a sloping top so rain will run off. But 2x4s would work also. On the top, sides, and bottom you need some of the greenhouse poly lock. This stuff will hold the poly tight even in a strong wind. I would just leave the ends open for access and ventilation. If that is still too hot I'd build the frame such that the bottom strip of poly lock was about 12 inches off the ground. That 12 inch area could then be opened if needed for more ventilation. With the suggested ventilation, I don't think humidity will be a problem. You only need about a 10-15 F temp increase. You can get that with quite a lot of ventilation. In a greenhouse, one air change every minute equals about a 10-15 F temp rise. If you're not getting enough heat, close the ends on the bottom with a door and close off the bottom at least part way. But if the sun is out you will need a lot of open area to avoid cooking things. The Fruitnut